Ask Dr. Z

Could you please assist with coding the following?

Indications and findings: ESRD patient noted swelling in the region of his LT chest/shoulder. MRI suggested a subcu mass superficial to the mid clavicle, suspicious for a complex loculated fluid collection, with angulation of the stent. The patient's stent graft in the axillary vein was known to be thrombosed.  I&D of abscess was performed; however, after one month, the wound has not completely closed. Today, the patient was found to have a chronic draining sinus, which extended down below the clavicle. There was an infected stent graft within the axillary vein identified at this level. The vein wall appears to have necrosed, and purulence was identified associated with the graft. After establishing proximal and distal control, the stent graft was removed. (From body of note:) ...I then made a curvilinear incision around the base of the previous LT shoulder wound....this was deepened and extended toward the clavicle....we also began exploring the base of the wound...the center of the wound...could be probed down and there appeared to be a sinus tract going below the level of the clavicle. We continued our excision of the surrounding tissue in an elliptical fashion along this sinus tract. At the base of the wound, we identified an FB...we identified a stent graft, going along with the history of previous LT axillary stent graft placement...we extended our incision medially and laterally along the course of the clavicle. This gave us better exposure along the segment of the axillary vein.

This procedure does not fit codes 35903 nor 35905 [site is shoulder/chest, instead of extremity or thorax (within pleural space)]. Do we need to go with an unlisted procedure code?